Propeller structure of a fan

ABSTRACT

A propeller structure of a fan, including a base section and multiple vanes. The base section has a base section surface and each vane has a vane surface for contacting with airflow. The propeller has multiple recesses distributed over the base section surface of the base section and the vane surfaces of the vanes. The recesses are formed on the base section surface and the vane surfaces for reducing the flow resistance between the airflow and the base section surface and the vane surfaces of propeller and the noise produced when the propeller rotates.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention is related to an improved propeller structure of afan, and more particularly a propeller structure in which multiplerecesses are formed on the base section surface and the vane surfacesfor reducing the flow resistance between the airflow and the basesection surface and the vane surfaces produced when the propellerrotates. In addition, the noise produced when the propeller rotates canbe also reduced.

2. Description of the Prior Art

Referring to FIGS. 7 and 8, the propeller 20 of a conventional fanincludes a base section 21 and several vanes 22. The base section 21 hasa base section surface 23 and each vane 22 has a vane surface 24. Thebase section surface 23 and the vane surfaces 24 are all polished forreducing the flow resistance against the propeller 20. However, when thepropeller 20 rotates, a parallel flow layer 25 is produced between thebase section surface 23 and the vane surfaces 24 and the ambientairflow. The parallel flow layer 25 cannot attach to the base sectionsurface 23 and the vane surfaces 24 so that a frictional resistanceexists between the base section surface 23 and the vane surfaces 24 andthe airflow. In addition, due to the frictional resistance between thebase section surface 23 and the vane surfaces 24 and the airflow, anoise will be produced.

SUMMARY OF THE INVENTION

It is therefore a primary object of the present invention to provide animproved propeller structure of a fan. Multiple recesses are formed onthe base section surface and the vane surfaces of the propeller. Whenthe propeller rotates, a turbulence layer will be produced. Theturbulence layer is easier to attach to the base section surface and thevane surfaces to form a thin air film for spacing the airflow from thebase section surface and the vane surfaces so as to reduce thefrictional effect between the airflow and the base section surface andthe vane surfaces. Therefore, the flow resistance between the airflowand the base section surface and the vane surfaces produced when thepropeller rotates can be reduced.

It is a further object of the present invention to provide the abovepropeller structure of the fan. By means of the recesses formed on thebase section surface and the vane surfaces of the propeller, the flowresistance between the propeller and the airflow can be reduced so thatthe noise produced when the propeller rotates can be reduced.

According to the above objects, the propeller structure of the fan ofthe present invention includes a base section and multiple vanes. Thebase section has a base section surface and each vane has a vane surfacefor contacting with airflow. The propeller has multiple recessesdistributed over the vane surfaces of the vanes. The recesses are formedon the vane surfaces for reducing the flow resistance between theairflow and the vane surfaces of the propeller and the noise producedwhen the propeller rotates.

In the above propeller structure, the recesses formed on the vanesurfaces are concave faces.

Still according to the above objects, the propeller structure of the fanof the present invention includes a base section and multiple vanes. Thebase section has a base section surface and each vane has a vane surfacefor contacting with airflow. The propeller has multiple recessesdistributed over the base section surface of the base section and thevane surfaces of the vanes. The recesses are formed on the base sectionsurface and the vane surfaces for reducing the flow resistance betweenthe airflow and the base section surface and the vane surfaces ofpropeller and the noise produced when the propeller rotates.

In the above propeller structure, the recesses formed on the basesection surface and the vane surfaces are concave faces.

The present invention can be best understood through the followingdescription and accompanying drawings wherein:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the present invention;

FIG. 2 is a front view of the present invention;

FIG. 3 is a side view of the present invention;

FIG. 4 is a perspective view of the present invention mounted in a fan;

FIG. 5 shows the airflow produced when the present invention is rotated;

FIG. 6 is a perspective view of another embodiment of the presentinvention;

FIG. 7 is a perspective view of a conventional fan; and

FIG. 8 shows the airflow produced when the conventional fan is rotated.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Please refer to FIGS. 1 to 6. The propeller structure 10 of the fan ofthe present invention includes a base section 11 and multiple vanes 12.The base section 11 has a base section surface 13 and each vane 11 has avane surface 14 for contacting with the airflow.

The present invention is characterized in that the propeller 10 hasmultiple recesses 15 distributed over the vane surfaces 14 of the vanes12 and the base section surface 13 of the base section 11. (The vanesurfaces 14 include two main upwind faces.) The recesses 15 are formedon the base section surface 13 and the vane surfaces 14 for reducing theflow resistance between the airflow and the base section surface 13 andthe vane surfaces 14 produced when the propeller 10 rotates. Also, therecesses 15 serve to reduce the noise produced when the propeller 10rotates.

In a preferred embodiment, the recesses 15 formed on the base sectionsurface 13 and the vane surfaces 14 are concave faces.

When the propeller 10 rotates, due to the recesses 15 formed on the basesection surface 13 and the vane surfaces 14, a turbulence layer 16 willbe produced, which is not easy to separate from the base section surface13 and the vane surfaces 14. That is, the turbulence layer 16 is easierto attach to the base section surface 13 and the vane surfaces 14 toform a thin air film for spacing the airflow from the base sectionsurface 13 and the vane surfaces 14 so as to reduce the frictionaleffect between the airflow and the base section surface 13 and the vanesurfaces 14. Therefore, the flow resistance between the airflow and thebase section surface 13 and the vane surfaces 14 produced when thepropeller 10 rotates can be reduced. In addition, the noise producedwhen the propeller 10 rotates can be reduced.

According to the above arrangement, the propeller structure of the fanof the present invention has the following advantages:

1. When the propeller rotates, due to the recesses formed on the basesection surface and the vane surfaces, a turbulence layer will beproduced. The turbulence layer is easier to attach to the base sectionsurface and the vane surfaces to form a thin air film for spacing theairflow from the base section surface and the vane surfaces so as toreduce the frictional effect between the airflow and the base sectionsurface and the vane surfaces. Therefore, the flow resistance betweenthe airflow and the base section surface and the vane surfaces producedwhen the propeller rotates can be reduced.

2. By means of the recesses formed on the base section surface and thevane surfaces of the propeller of the present invention, the flowresistance between the propeller and the airflow can be reduced so thatthe noise produced when the propeller rotates can be reduced.

The above embodiments are only used to illustrate the present invention,not intended to limit the scope thereof. Many modifications of the aboveembodiments can be made without departing from the spirit of the presentinvention.

1. A propeller structure of a fan, comprising a base section andmultiple vanes, the base section having a base section surface and eachvane having a vane surface for contacting with airflow, said propellerstructure being characterized in that the propeller has multiplerecesses distributed over the vane surfaces of the vanes, the recessesbeing formed on the vane surfaces for reducing the flow resistancebetween the airflow and the vane surfaces of the propeller and the noiseproduced when the propeller rotates.
 2. The propeller structure asclaimed in claim 1, wherein the recesses formed on the vane surfaces areconcave faces.
 3. A propeller structure of a fan, comprising a basesection and multiple vanes, the base section having a base sectionsurface and each vane having a vane surface for contacting with airflow,said propeller structure being characterized in that the propeller hasmultiple recesses distributed over the base section surface of the basesection and the vane surfaces of the vanes, the recesses being formed onthe base section surface and the vane surfaces for reducing the flowresistance between the airflow and the base section surface and the vanesurfaces of propeller and the noise produced when the propeller rotates.4. The propeller structure as claimed in claim 3, wherein the recessesformed on the base section surface and the vane surfaces are concavefaces.